The present invention relates to games rackets of the type which are used to play tennis, squash, badminton, and other racket games.
While the present invention may be employed in a wide variety of rackets of the type used to play such games as tennis, squash, badminton, and the like, reference herein will be made to oval headed rackets, such as tennis rackets, and to circular headed rackets, such as squash rackets, although such reference is meant to include rackets of the type used for playing other games as well.
Tennis rackets generally comprise a frame including a handle made of metal or wood having a grip attached at one end and a substantially oval head attached at the other end. A netting, generally of nylon or catgut, is stretched across the head, with the most common form of netting comprising a set of strings extending in a direction parallel to the longitudinal axis of the handle (hereinafter referred to as being in the vertical direction) with a second set of strings extending in a direction perpendicular to the longitudinal axis of the handle (hereinafter referred to as being in the horizontal direction). Generally, the horizontal and vertical strings are weaved together such that any horizontal string will overlie and underlie any two adjacent vertical strings, and any vertical string will overlie and underlie any two adjacent horizontal strings.
There have been rackets made heretofore which have employed netting patterns including sets of strings going other than in the standard horizontal and vertical patterns. For example, in U.S. Pat. No. 1,687,322 entitled GAMES RACKET which issued on Oct. 9, 1928 to C. A. Claremont, a racket is described which employs wire stringing in a racket having an elastic rim. The wire stringing of the racket described by Claremont is in a diagonal pattern in which two sets of parallel strings are interlaced with each other and all of the strings are skewed with respect to the longitudinal axis of the handle.
Another tennis racket which employs two sets of interlaced diagonal strings is described in U.S. Pat. No. 3,917,267 entitled TENNIS RACKET which issued on Nov. 4, 1975 to C. A. McGrath. In the racket described in the patents issued to Claremont and to McGrath two sets of interlaced diagonal strings were used, where the term "diagonal" is used to mean the direction of the strings is oblique to the longitudinal axis of the handle and the term "interlaced" is used to mean that adjacent strings of one set of strings are alternately weaved above and below adjacent strings of the other set of strings.
In British Pat. No. 5177 entitled IMPROVEMENTS IN THE METHOD OF STRINGING LAWN TENNIS, RACQUET, AND OTHER BATS which issued on Jan. 27, 1886 to W. D. Nightingale, a tennis racket is described which employs three sets of strings, two sets being diagonal and the third set being horizontal. When the racket is viewed from the front, all of the strings of one of the diagonal sets overlie all of the strings of the other diagonal set. The strings of the horizontal set are weaved through the two diagonal sets in a pattern in which the horizontal strings overlie all of the strings of the upper diagonal set and underlie all of the strings of the lower diagonal set. In addition, none of the intersections of the horizontal strings with the strings of either of the diagonal set coincides with an intersection of a diagonal string from one diagonal set with a diagonal string from the other diagonal set.
A problem which has been observed with the tennis racket described by Nightingale which employed 20 horizontal strings and 18 strings in each diagonal is that if the strings are tensioned in a normal range of from 40 to 75 pounds, the racket will not play well. It has been found that the poor play of the racket described by Nightingale results from the large number of strings which he employed.